Lithium iron phosphate cells refer to lithium ion batteries that use lithium iron phosphate as a positive electrode material. The positive materials of lithium-ion batteries mainly include lithium cobalt oxide, lithium manganate, lithium nickelate, ternary materials, lithium iron phosphate, etc.
Among them, lithium cobalt oxide is the cathode material used in the vast majority of lithium-ion battery wholesale. In terms of material principles, lithium iron phosphate is also a process of intercalation and deintercalation, which is exactly the same as that of lithium cobaltate and lithium manganate.
1. Introduction of lithium iron phosphate cells
Lithium iron phosphate battery is a lithium ion secondary battery, one of the primary uses is for power batteries, which has great advantages over NI-MH and Ni-Cd batteries. The charge and discharge power of lithium iron phosphate cells for sale is relatively high, and the charge and discharge power can reach more than 90% under the condition of rate discharge.
In the metal trading market, cobalt (Co) is the most expensive, and there is not much storage, nickel (Ni) and manganese (Mn) are relatively cheap, and iron (Fe) is the cheapest. The price of cathode materials is also consistent with the price of these metals.
Therefore, the lithium-ion battery made of LiFePO4 cathode material should be the cheapest. Another feature of it is that it is non-polluting to the environment.
2. Structure and working principle of lithium iron phosphate cells
The inside of the LiFePO4 battery is LiFePO4 with an olivine structure as the positive electrode of the battery, which is connected to the positive electrode of the battery by an aluminum foil, with a polymer barrier in the middle, which separates the positive electrode from the negative electrode.
But the lithium-ion Li+ can pass through but the electron e- cannot pass through. The right side is the battery negative electrode composed of carbon (graphite), which is connected to the negative electrode of the battery by copper foil. Between the upper and lower ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metal casing.
When the LiFePO4 battery is charged, the lithium-ion Li+ in the positive electrode moves to the negative electrode through the polymer barrier; during the discharge process of the lithium iron phosphate battery, the lithium-ion Li+ in the negative electrode moves to the positive electrode through the barrier. Lithium-ion batteries are named after lithium ions that move back and forth during charging and discharging.
3. The primary function of lithium iron phosphate cells
The nominal voltage of LiFePO4 battery is 3.2V, the stop charging voltage is 3.6V, and the stop discharging voltage is 2.0V. Because the quality and process of the positive and negative materials and electrolyte materials used by various manufacturers are different, there will be some differences in their functions.
The capacity of lithium iron phosphate power batteries is quite different and can be divided into three categories: small tenths to a few milliamp hours, medium tens of milliamp hours, and large hundreds of milliamp hours. There are also some differences in the same parameters of different types of batteries.
Now the widely used cylindrical lithium-ion battery sizes are 18mm in diameter, and 650mm in height.
4. The characteristics of lithium iron phosphate cells
High power output: standard discharge is 2 ~ 5C, continuous high current discharge can reach 10C, instantaneous pulse discharge (10S) can reach 20C;
Excellent performance at high temperature: when the external temperature is 65 °C, the internal temperature is as high as 95 °C, and the temperature at the end of battery discharge can reach 160 °C, the structure of the battery is safe and intact;
Even if the battery is damaged internally or externally, the lithium iron phosphate battery does not burn, does not explode, and has the best safety; excellent cycle life, after 500 cycles, its discharge capacity is still greater than 95%;
No damage even from over-discharge to zero volts; fast charging; low cost; no pollution to the environment.
5. The application of lithium iron phosphate power battery
Large electric vehicles: buses, electric cars, sightseeing vehicles and hybrid vehicles, etc.;
Light electric vehicles: electric bicycles, golf carts, small flat-panel battery vehicles, forklifts, cleaning vehicles, electric wheelchairs, etc.;
Power tools: electric drills, chainsaws, lawn mowers, etc.;
Remote control cars, boats, airplanes and other toys;
Lithium iron phosphate batteries are used in energy storage equipment for solar and wind power generation;
UPS and emergency lights, warning lights and miner's lights (the best safety);
Substitute 3V primary lithium battery and 9V nickel-cadmium or nickel-metal hydride rechargeable battery in camera (same size);
Small medical equipment and portable equipment, etc.